Development of muscarinic cholinergic inhibition of adenylate cyclase in embryonic chick heart. Its relationship to changes in the inhibitory guanine nucleotide regulatory protein.

摘要: Parasympathetic and sympathetic innervation of the embryonic chick heart proceed non-coordinately. beta-Adrenergic agonists mediate an increase in beating rate prior to ingrowth vagus nerve (Culver, N. G., Fishman, D. A. (1977) Am. J. Physiol. 232, R116-R123) while muscarinic exert relatively little effect on hearts 2-4 days ovo (Papanno, (1979) Pharmacol. Rev. 29, 3-33). Studies developmental changes ability inhibit adenylate cyclase activity their relationship development a physiologic response stimulation have been inconclusive. In current studies isoproterenol stimulate did not change during development. Maximum above basal was 760 pmol cAMP/10 min/mg proterin with IC50 1.5 X 10(-6) M for homogenates 2 1/2, 3 10 posthatching. However, inhibition isoproterenol-stimulated by carbamylcholine increased from 7.6% 16 +/- 5.0 microM at day 1/2 29% 0.4 0.1 43% 0.6 Since previous data had demonstrated presence receptors as early (Galper, B., Klein, W., Catterall, W. Biol. Chem. 252, 8692-8699), guanine nucleotide-coupling proteins were carried out determine whether uncoupled response. pertussis toxin-catalyzed ADP-ribosylation [32P]NAD two ADP-ribosylated 39,000 41,000 kDa, respectively. Both immunoblotting antibody 39-kDa nucleotide-binding protein bovine brain that alpha 1.8-fold between another parallel extent activity.(ABSTRACT TRUNCATED AT 400 WORDS)